Production of alumina



Nov. 1, 1960 G. L. HERVERT EVAL PRODUCTION OF' ALUMINA Filed Oct. 1.1958 Hydrogen Alum/na &

Alum/'num Reactor I Mo/re -Up Wo/er /P/us Promoter Unreocfeo' Alum/'numF/nes Heal Exchanger /A/ V E/V T0 RS: George L. Hen/erf By Her/non S.Bloch United States Patent O PRODUCTION F ALUMINA George L. Hervert,Downers Grove, and Herman S. Bloch, Skoln'e, lil., assignors, by mesneassignments, to Universal Oil Products Company, Des Plaines, Ill., acorporation of Delaware Filed Get. 1, 1958, Ser. No. 764,669

4 Claims. (Cl. 23-143) This yapplication is a continuation-in-part ofour copending application Serial No. 520,802 led July 8, 1955, nowPatent No. 2,855,275, which is a continuation-in-part of our co-pendingapplication Serial No. 315,414 filed October l7, 1952, now abandoned.

'Ihis invention relates to the preparation of alumina and morespecifically to a method of preparing alumina by the interaction ofwater and metallic aluminum in the presence of organic catalysts.

Alumina, either as the hydrate vor the anhydrous form as aluminum oxideis widely used in the petroleum and many other branches of chemicalindustry. It has been employed in the petroleum industry as a catalystfor hydrocarbon conversion processes, as a support for catalyticallyactive materials to be used in hydrocarbon con- .Version processes, and4as a dehydrating agent. It is widely used in other elds of chemicalindustry for the same purposes. The activated forms which are consideredto be merely modioations of aluminum oxide and its hydrates areespecially known for their pronounced catalytic activity and adsorptivecapacity. The use of alumina as a refractory is also well known. Aluminain the `form of corundum has been found suitable for use in themanufacture of certain types of refractory and ceramic materials. Highpurity alumina is also used medicinally. In other uses alumina is mixedor blended with other components to produce substances of modifiedproperties.

` In one modification of the invention the alumina produced under theconditions of our invention is in an extremely iine state of divisionand requires no grinding to render. it impalpable, nevertheless it isrelatively easily lterable and may thus be readily separated from theliquid in which it is formed so that the latter may be reused. Thealumina in an extremely finely divided form, that is, an impalpablepowder, is especially suitable for cosmetics, medicinals, fineabrasives, or agricultural or military dusting purposes.

It is an object of our invention to provide a new process for theproduction of alumina and further to produce high purity alumina.

It is another object of our invention to provide a new process for theproduction of extremely nely divided alumina and further to produce this[alumina in a very pure state.

Alumina or aluminum hydrate is present in various modifications, themore common types of alumina being the following:

Alpha-alumina, ioften known as corundum, is the form stable attemperatures over about 1800" F.

Gamma-alumina is very stable but changes to alphaalumina at temperaturesabove about l800 F.

Epsilon-alumina is the alumina formed in thin films on the surface ofmetallic aluminum `during oxidation by dry or wet air or oxygen.

Gamma-A12O3-3H2O or gibbsite is prepared by aging boehmite in -a coldbasic solution.

Alpha-A12O3-3H2O or bayerite is also formed by aging Patented Nov. 1,1960 boehmite in 'a cold basic solution but is unstable and gradually istransformed into gibbsite.

Gamma-A12O3-H2O or boehmite may be prepared in a variety of ways, one ofthe simplest being to add ammonium hydroxide to a water solution ofaluminum chloride. The material `originally precipitated is thought tobe an amorphous alumina ilock which rapidly grows in crystal sizeyielding crystalline boehmite. Aging the boehmite in ammonium hydroxidesolution transforms the boehmite rst to meta-stable bayerite and finallyto the stable gibbsite.

Alpha-A12O3H2O or diaspore occurs abundantly in nature.

In the specification and claims the word alumina will mean 'one or moreof these various modifications, either as anhydrous alumina or aluminahydrate or aluminum hydroxide unless otherwise specifically noted.

By varying the conditions of the process of this invention it will beshown that some of the various modifications of alumina as hereinbeforedescribed may be obtained.

'I'he usual commercial method of producing alumina is by purifying oresin which the oxide is present. Another method is by the precipitation ofaluminum hydroxide from its salts, for example, by the addition ofammonia to an aqueous solution `of aluminum sulfate. However, thephysical form of the product produced in our process is much superiorsince it is crystalline and easily ilterable, while the precipitated`aluminum hydroxide is a gel that is filtered with difficulty.

We have now discovered and our invention broadly comprises an improvedmethod for preparing alumina by reacting yaluminum with water underspecific conditions and in the presence of certain water soluble organiccatalytic substances. Hydrogen in a very pure state is produced as aby-product of thisy reaction.

It is recognized that the art teaches that alumina is `formed on thesurface of aluminum upon exposure to dry or wet air or oxygen; however,it is yalways referred to as a protective coating of alumina whichprevents the aluminum metal under this coating from being converted tothe oxide. Our invention, however, is such that a substantial amount,and in the more desirable aspect, the entire amount of aluminum isconverted to the oxide and is separated as such, that is substantiallyfree from aluminum metal. In the prior art the protective coating istaught to be of a tenacious nature, in that it adheres rigidly to thealuminum metal, while in our invention alumina is formed in a state thatis easily separated from the reactants. In the preferred embodiments ofour invention all of the aluminum is converted to the hydrated oxide andit is only necessary to separate water and catalyst therefrom which maybe done by appropriate filtering or heating steps. In other modes ofoperation where all of the aluminum is not converted to the oxide, thetwo `solids occur substantially as distinct separate solids which do notadhere and are not attached to each other to any appreciable extent andmay thus be separated by any satisfactory means, such as centrifugalseparation, tlotation, and the like. It is not necessary and, in fact,it is undesirable that the separation be effected by some cutting means,such as Iscraping or tumbling to remove the oxide from the surface ofthe metal since under the condition of operation of our inventionalumina is present, distinct and separate from the aluminum metal fromwhich it is formed.

The aluminum to be used in our process can be any commercially availablealuminum although if a high purity alumina product is desired it ispreferable to start with high purity aluminum. It is also within thescope of this invention to use aluminum alloys, however, since thepresent process will produce very pure alumina, it is a preferredembodiment of the present invention to react aluminum of 99.5-{% purityin water to produce a high purity alumina product.

The degree of subdivision of the aluminum is another factor determiningthe Vrate of the reaction. The smaller the size of the particles thegreater the surface area of aluminum exposed to the water Ifor reaction.Powdered aluminum may be used, or aluminum turnings, or granulatedaluminum. Aluminum pellets prepared by dropping molten aluminum intowater have likewise proven to be very satisfactory for producing aluminaby the process of our invention, those pellets below about an inch inaverage diameter being preferred.

One embodiment of the present invention comprises agitating the aluminumand water and catalytic substances sufficiently so that the reaction toproduce alumina proceeds at a desirable rate. The reaction velocity isdependent upon the temperature of the reactants, the degree ofsubdivision of the aluminum, and the degree of agitation given themixture. Thus a reaction that proceeds slowly at a temperature of 212 F.with only a mild agitation or shaking of the mixture will proceed veryrapidly if the mixture is vigorously agitated. At a temperature of 572F., on the other hand, the reaction proceeds relatively rapidly evenwith a mild degree of agitation. However, if the mixture is subjected tovigorous agitation, the time necessary for complete reaction issubstantially decreased.

A preferred embodiment of the present invention relates to the processfor producing hydrated alumina which comprises reacting aluminum withwater in the presence of certain water soluble organic catalyticsubstances, agitating the mixture to form alumina, maintaining apressure sufficient to keep at least a portion of the water in theliquid phase and separately recovering alumina therefrom.

It is a desirable feature of the present invention that liquid water bepresent and it is thus necessary when temperatures above the boilingpoint are employed to effect the reaction under suicient pressure tomaintain a liquid phase of water. The critical temperature of water is705 .2 F.; the definition of the critical temperature being thattemperature above which a gas cannot be liqueiied by pressure alone. Itis desirable to use liquid water since it is much easier to haveintimate contact and especially mixing between the aluminum and wateraccomplished i-f there is a liquid phase. However, the reaction willalso proceed if the water is present in the vapor phase, especially atsuperatmospheric pressures, and while it is a desired feature to keepwater in the liquid phase, it is not at all a limiting feature.Experiments conducted at temperatures near the critical temperature atpressures suflicient to maintain water in the liquid phase have beenentirely successful and the reaction proceeds at a very rapid rate.Also, experiments conducted at temperatures near the criticaltemperature and at pressures insufficient to maintain water in theliquid phase have been entirely successful. From a practical standpoint,the upper temperature can be limited to about 850 F. since temperaturesabove this cause excessive decomposition of most of the effectiveorganic nitrogen-base activators.

In another embodiment the present invention relates to a process forproducing hydrated alumina which comprises reacting aluminum with waterin the presence of a non-metallic organic base to form alumina andseparately recovering alumina therefrom,

In a specific embodiment the present invention relates to a process forproducing alumina which comprises reacting aluminum with water in thepresence of a water soluble organic nitrogen base to form alumina andseparating the resultant alumina from the reaction mixture.

In another specific embodiment the present invention relates to aprocess for producing alumina which comprises reacting aluminum withwater in the presence of ethanolamine to form alumina and separatelyrecovering alumina therefrom.

2,958,582. f.. f f

In a further embodiment the present invention relates to a process forproducing alumina which comprises reacting metallic aluminum at atemperature of from about 30 F. to about 705 F. with liquid water havinga water soluble organic nitrogen-containing base dissolved therein.

The water soluble organic nitrogen base used in this reaction acts as anaccelerant to speed the reaction of aluminum with water in order to`form the desired alumina. We have discovered, and our invention isbased on the discovery, that water soluble organic nitrogen bases arecatalysts for the reaction between aluminum and water to form alumina.It is the catalytic properties not merely the physical or chemicalproperties, of the organic bases which causes them to be catalysts forthis reaction. rl`he exact reason why the lwater soluble organicnitrogen bases are catalysts for this speciiic reason is not known, andthe discovery was unexpected. Where the base used in this process is ofsuch a nature that it reacts or promotes reaction with walls of anordinary reaction vessel it is preferred, of course, that the reactionvessel be constructed of material inert to the reactants in order thatcorrosion and contamination of the products may be avoided.

A preferred step of the present invention is thereaction of aluminumwith water in the presence of a water soluble nitrogen-containingorganic base, such as ethanolamine. When a water solublenitrogen-containing organic base is used as a catalyst in this reaction,the reaction will proceed at a much lower temperature than if thesebases are absent. For example, if 18 grams of aluminum and 200 grams ofdistilled water are placed in a pressure autoclave and the reactionmixture is heated to 200 F., only a very small amount of reaction isnoticeable within 24 hours; however, if a catalytic amount ofmonoethanolamine is introduced the reaction will have been substantiallycompleted in 6 hours.

Further, in the presence of the water soluble nitrogencontaining organicbases, aluminum alloys which are inert to the action of water alone evenat high temperatures (such as 2S aluminum containing 1% Fe, 0.2% Mn,0.1% Cu, 0.2% Si, 0.05% Ga, 0.03% Mg, and 0.008% Hi) react readily atrelatively mild temperatures.

Since the water soluble organic base `acts as an accelerant or catalystit is preferably used in very low concentrations. The water solubleorganic nitrogen base need not `be completely soluble in water but itneed only be solubleto the extent that it is needed as a catalyst. Forexample if only 2% by weight of a specilic Vorganic nitrogen-containingbase is necessary to catalyze the reaction, it is only necessary for thebase to be water soluble to the extent of 2%. The base, however, must bewater soluble at the reaction temperature. We have found that thereis arange of concentrations in which the base exhibits maximum activity. Forexample, we have found that concentrations of monoethanolamine used as acatalyst within the nange of from about 4% to about 20% have the highestcatalytic eifect and concentrations lesser or greater than these do nothave as great a catalytic effect. Similarly, with n-butylamine maximumreaction velocity leading to substantially complete conversion of thealuminum in a minimum time, occurs with amine concentrations of about 4%to about 23%. Any amount of a base, used as an accelerant or catalystherein mentioned Vwill be a catalytic amount or referred' to as acatalytic amount. The concentration of theA catalyst in thewater-catalyst solution will usually be within the range of from about0.05% to about 50% by weight.

The catalyst may consist of water soluble nitrogen-containing organicbases such as:

(1) Primary, secondary, and tertiary alkylamines, as for example,ethylamine, diethylarnine and triethylamine, butylamine.

(2) .The alkanolamines, for example the ethanolamines, such asmonoethanolamine, diethauolamine and triethanolamine.

'the product alumina by heating or oxidation.

(3) Aryl-alkyl amines (primary, secondary and tertiary) such asbenzylamine, methylaniline and dimethylaniline.

l(4) Pyridine and its homologs, such as the picolines, lutidines andcollidines.

(5) Piperidine and its homologs.

In general, we have found that the organic nitrogenous bases fallroughly into three classes: those having, in aqueous solution,ionization constants equal to or greater than -5 and exhibiting pHvalues (for 2-25% solutions) above about 12, which are highly activecatalysts for dissolving aluminum; those having ionization constantsequal to or below about l0-9 and exhibiting pH values of less than about11, which lare poor catalysts; and those exhibiting intermediate pHvalues (11 to 12) and having intermediate ionization constants (10-6 to`10r), which are fair catalysts.

It is our belief, although we do not intend the scope of this inventionto be limited by this theory, that the nitrogen bases catalyze thereaction of aluminum with water by continuously dissolving theprotective aluminum oxide lm thereby exposing fresh aluminum surface forreaction. It is possible, for example, that the oxide film is removed bythe formation of aluminum-nitrogen base complexes which are suliicientlysoluble to be carried into the aqueous phase wherein alumina isprecipitated from the complex and the nitrogen base regenerated forfurther use. i As hereinbefore stated the organic nitrogen-containingibase must be water soluble, but need only be water soluble to theextent that it is neded as a catalyst at the reaction conditions. Itmay, therefore, be considered that the aluminum is reacted with waterhaving an organic nitrogen-containing base dissolved therein or it lmaybe stated that the aluminum is reacted with an aqueous solution ofanorganic nitrogen base. The word solution is intentionally used so asto indicate that the organic base is soluble in the water to the extentrequired. p Several of the advantages of our process have hereinbeforebeen mentioned. The process also has the advantage of introducing onlyvolatile materials into the reaction mixture and these :may easily beremoved from The organic nitrogen-containing bases also have theadvantage of having a wide variety of boiling points. Therefore, when itis desired to conduct the alumina-Water reaction at a high temperaturean organic nitrogen-containing base with a high boiling point may beused. This is a definite `advantage. over other processes in which avolatile catalyst is used, since in our process a high concentration ofthe organic nitrogen base may more easily be maintained in the liquidphase.

IMuch has already been made of the fact that it is preferable to use aliquid phase of Water and, therefore, the preferred` upper limit oftemperature that the reaction may proceed at is the critical temperatureof water of ,about 705 F. The reaction requires increasingly longerperiods of time as the temperature of the reaction is decreased andwhere the time of the reaction is not important it is possible to effectthe reaction at temperatures down to the freezing point of the water andcatalyst solution, that is, about 32 F. or lower, although the reactionis quite slow at such low temperatures. Thus the temperature rangeh inwhich the reaction between aluminum and water in the presence of acatalyst is effected `is from about 32 F. to about 850 F.

Within the range of temperatures in which the reaction may be effectedthe alumina is produced in various modiiications. In the lower range oftemperatures, for eX- ample, from about 32 F. to about 160 F. thealumina i is produced in an extremely iinely divided form that is, vthealumina Ais produced in this form directly without the need of attritionor grinding. To obtain this nely `divided alumina, or impalpable powderdirectly, the reaction is effected at relatively low temperatures whichnecessitate relatively long reaction periods. The preferred uppertemperature limit is about F., however, temperatures above this may beused with the understanding that if the reaction is effected attemperatures above about 160 F. alumina particles will be formed in anincreasingly larger` average crystalline size. The reaction requiresincreasingly longer periods of time as the temperature of the reactionis decreased and where the time of the reaction is not important it ispossible to effect the reaction at temperature down to the freezingpoint of water and catalyst solution, that is, about 30 F. Thus thepreferred range of temperatures in which the reaction between aluminum`and water in the presence of a catalyst is eifected to produce the mostiinely divided form of alumina is from about 30 F. to about 160 F. Thealumina produced in this reaction is further characterized as beinggibbsite. An analysis of the alumina product formed at 400 F. shows thatthe product is chiey gibbsite, however, traces of Boehmite, a modicationof alumina, are evidenced.

As the temperature of the reaction is increased in excess of 400 F. thepercent of Boehmi'te in the product is accordingly increased, and at atemperature of approximately 650 F. the product of the reaction between`aluminum Iand water in the presence of a catalyst is analyzed `as beingBoehmite. The temperature at which the reaction is carried `out alsoaffects the size of the alumina crystals. The reaction between aluminumIand water at high temperatures will produce larger crystals whichlafter drying appear to be rough enough to use as an abrasive. Theamount of organic nitrogen base activator present also affects theIcrystallite size, larger average particle sizes being obtained withlower concentrations of activator. Further, particle size distributiondata on A1203 produced from the monoethanolamine catalyzed reaction at212 F. indicate that smaller particles of alumina are produced at higheramine concentrations.

The reaction may be effected in any suitable type of equipment whereinthe reactants -are subjected to agitation `and preferably to vigorousstirring. The oper-ation may be carried out in continuous or batch-wisefashion. When temperatures above the boiling point of water are employedand the reaction is performed with water in the iliquid phase it is, ofcourse, necessary that the reaction vessel be capable of withstandingpressures su'icient to maintain `a liquid phase of water. In small scaleproduction of alumina by this process a rotating pressure autoclave issatisfactory. When the temperatures employed are below the boiling pointof water the reaction may be effected in ordinary open equipment, inwhich a means is provided for the safe escape of hydrogen and forvigorous stirring or agitation of the reagents. It is, however,necessary that the process equipment be constructed of 'such materialsthat they are not Aaifected by water or aluminum rand/or the cata-'lysts used so that undesirable elements are not introduced into thedesired alumina product. However, if the presence of these foreignsubstances is: not objectionable the above precautions need not beadhered to. Hydrogen is produced as a by-product of the reaction and lameans of venting must be Iprovided if the pressure build-up caused bythe production of this hydrogen is to be avoided. If the equipment willwithstand this additional pressure, however, it is not necessa-ry tovent the hydrogen continuously.

The figure of the accompanying diagrammatic flow drawing illustrates aparticular method for continuously conducting the process whichincorporates several speciiic embodiments of the invention. Forsimplification, equipment `such yas valves, pumps, land similarappurtenances have been omitted in the drawing. These are wel-l knownand are not essential to the understanding of the invention.

Referring to the drawing, aluminum in the form of liquid phase.

,chips or pellets is passed through lineY 1 into reactor 2 .which lisprovided with a stirring or agitating devi-ce 3 ,and a means of ventinghydrogen 4. Water lat approximately 212 F. plus a promoter areintroduced into reactor 2 VtlhroLgh line 5. The reaction betweenialuminum and Water is allowed to proceed in reactor 2 until thealuminum is essentially entirely convertedto alumina yand the alumina,traces of aluminum lines and water form a slurry in the reactor which iswithdrawn through line 6. Tlhe slurry in line 6 is passed intoyseparator 7 which is provided with a stirring device S which pro-.vides suiiicient agitation to aid in suspending the alumina but allowsthe unreacted aluminum fines to settle from the slurry to the bottom `ofthe separator. 'The -aluminum fines are periodically withdrawn throughline 10 and are passed through valve 11 and line 12 to be reclaimed andmay be again introduced into reactor 2.. The alumina slurry invseparator 7 is ywithdrawn through line 9 and the slurry is introducedinto filter 13. Filter 13 may be Iany suitable iiltering means such as acontinuous rotary lilter `or it may be any usual commercial batch ilterythat may be found suitable for this process. The alumina is withdrawnfrom the tilter through line 14 and may be subjected to furthertreatment such as washing to remo-ve traces of the promoter o-r thealumina may be directly dried and calcined for any of the various useshereinbefore mentioned. The water and promoter from ilter 13 are removedthrough line 15 and are joined by 1a make-up water plus promoter streamin line 16 after which the combined stream is passed through heatexchanger 17 and into line 5. In heat exchanger 17 the water pluspromoter are raised to the desired reaction temperature. If it ispreferred to effect the reaction at temperatures above the normalboiling point of water it is necessary that reactor 2 be constructed soIas to withstand process pressures at least suflicient to maintain a Inthese modes of high temperature and pressure `operation it may bedesirable to substitute a direct yheater for heat exchanger 17.

The precipitated alumina formed in our reaction need merely be iilteredfrom the water-organic nitrogen base mixture and water washed to beready for use; in many LiCases, especially Where a `subsequentcalcination is involved in the use of the alumina, even the waterWashing is unnecessary since no foreign non-volatile materials areintroduced during the preparation of the alumina; the 'absence `offoreign metals in the product alumina is, in fact, a feature of thismethod of preparation. The organic nitrogen base is not consumed in thereaction and the iiltrate from the alumina may, therefore, be reused forfurther reaction with aluminum.

The following examples are given to illustrate our invention but are notgiven for the purpose of unduly li-miting the generally broad scope ofsaid invention.

Example l 18 grams of aluminum pellets (99.9-{-% purity), of about 1% to5/8 diameter, and 200 grams of distilled water were placed in anIpatieii-type autoclave having a capacity of 850 milliliters; theautoclave was iitted internally with a Pyrex liner. After sealing, theautoclave was flushed with nitrogen and subsequently heated to atemperature of 392 F. The temperature was maintained 4at this level fora period of 24 hours, after which time an inspection indicated that onlya very minor amount of the metallic aluminum had reacted with the water,forming thereby alumina. The alumina product was dried at 230 F. for 1hour, and an analysis thereof indicated that the product was gibbsite.These results indicated that, at an elevated temperature of 392 F., andconditions as outlined above, the reaction between aluminum and water inthe absence of any cata-lytic material, is extremely slow and would notbe fan attractive comercial method for producing alumina.

' 8 Example II 200 grams iof distilled water `and 18 grams off aluminumchips (99.9{-% purity) approximately 1/16" wide, 1% long land 1/16"thick, were placed in a two-liter Pyrex flask equipped with a six-blade,high-speed Pyrex stirrer. The alumina and the water were maintained atroom temperature (approximately F.) for a period of 15 days. At thetermination of this period, only a very small amount of alumina wasevident within the Pty-rex flask; the greater bulk tof the aluminumremained unchanged.

Example III 18 grams of aluminum chips (99.9|% purity) and 0.837 mol ofdi-ethylene triamine were added to a 2l1ter Pyrex flask equipped withtwo water condensers and a 6-blade Pyrex stirrer. The speed of thestirrer was maintained at 1500 r.p.m. by means of a Variac. A total of414 grams of distilled water was added to the reaction vessel to bringthe total contents therein to a level of 500 grams. The temperature wasmaintained for 6 hours at a level of 99.5 C. After cooling, the aluminawas separated from the remaining contents within the reaction vessel, bydecantation; the alumina was Washed with distilled water and thereafterdried at C. for 3 hours. The quantity of aluminum which had reacted withthe water, was calculated on the basis of the quantity of metallicaluminum recovered from the reaction mixture remaining within the Pyrexvessel. Through the utilization of di-ethylene triamine, 81.1% of thealuminum had reacted with the water forming thereby alumina.

The foregoing examples clearly indicate that we have provided a newmethod for the production of alumina, and further illustrate the benetsafforded through the utilization thereof. Insigniiicant modifications,readily apparent to one skilled in the art of manufacturing alumina, areintended to be within the scope and spirit of our invention; theinvention is not intended to be restricted beyond the scope of theappended claims.

We claim as our invention:

1. A process for producing hydrated alumina which comprises reactingmetallic aluminum with liquid water having dissolved therein a catalyticamount of di-ethylene triamine, at a temperature within the range offrom about 30 F. to about 705 F. for a sufficient time to form alumina,and separating the resulting alumina vfrom the reaction mixture.

2. The process of claim 1 further characterized `in that saidtemperature is within the range of from about 30 F. to about F. wherebythe alumina is produced in iinely divided form.

3. The process of claim 1 further characterized in that said temperatureis within the range of from about 30 F. to about 400 F. whereby thealumina is produced in the form of gibbsite. Y

4. The process of claim 1 further characterized inthat said temperatureis in excess of 400 F. whereby'the alumina is produced in the form ofBoehmite.

References Cited in the file of this patent UNITED STATES PATENTS l2,872,418 Hervert et al. Feb. 3, 1959 OTHER REFERENCES Mellor:Comprehensive Treatise on Inorganic and Theoretical Chemistry, vol. 5,page 212 (1924), Longmans Green and Co., New York, NY.

Thorpe: Dictionary of Applied Chennstry, 4th edltion, v01. 1, page 274(1937), Longmans Green and Co., Neu/York, N.Y. .Y i

1. A PROCESS FOR PRODUCING HYDRATED ALUMINA WHICH COMPRISES REACTINGMETALLIC ALUMINUM WITH LIQUID WATER HAVING DISSOLVED THEREIN A CATALYTICAMOUNT OF DI-ETHYLENE TRIAMINE AT A TEMPERATURE WITHIN THE RANGE OF FROMABOUT 30*F. TO ABOUT 705*F. FOR A SUFFICEINT TIME TO FORM ALUMINA ANDSEPARATING THE RESULTING ALUMINA FROM THE REACTION MIXTURE.